Search

This paper presents the results of laboratory investigation conducted with reservoir rock plugs recovered from the Gas reservoir in the North West Shelf of Western Australia. The experiments were conducted in reservoir conditions (High Pressure (HP = 41.37 MPa) and High Temperature (HT = 433.15 K)). The aim of this study was to determine residual gas saturation and quantify the effect of reservoir conditions (HP/HT) on gas-brine relative permeability. The experimental data have been analysed using relative permeability concept. Both wetting and nonwetting phase relative permeability were generated using explicit methods, i.e, Hasslar and Corey model (Power Model). The power model is then used to match experimental data through modifying the parameters of the Corey correlation. Several core plugs were used by this study representing different reservoir quality rocks in the reservoir. The core plugs were in different dimensions, the short core plugs measured around 5 cm in length while the long core plug measured 19.41 cm. The aim of using longer core plugs was to minimise the effect of capillarity and end-effects on the relative permeability measurements. Since permeability measurement under the test conditions depends on pressure drop across the core plugs. Cited as : Sidiq, H., Amin, B., Kennaird, T. The study of relative permeability and residual gas saturation at high pressures and high temperatures. Advances in Geo-Energy Research, 2017, 1(1): 64-68, doi: 10.26804/ager.2017.01.06

Conventional petrophysical characterizations are often based on direct laboratory measurements. Although they provide accurate results, such measurements are time-consuming and limited by instrument and environment. What’s more, in the geo- resource energy industry, availability and cuttings of core plugs are difficult. Because of these reasons, virtual digital core technology is of increasing interest due to its capability of characterizing rock samples without physical cores and experiments. Virtual digital core technology, also known as digital rock physics, is used to discover, understand and model relationships between material, fluid composition, rock microstructure and macro equivalent physical properties. Based on actual geological conditions, modern mathematical methods and imaging technology, the digital model of the core or porous media is created to carry out physical field numerical simulation. In this review, the methods for constructing digital porous media are introduced first, then the characterization of thin rock cross section and the capillary pressure curve using scanning electron microscope image under mixed wetting are presented. Finally, we summarize the hydraulic flow unit methods in petrophysical classification. Cited as : Chen, X., Zhou, Y. Applications of digital core analysis and hydraulic flow units in petrophysical characterization. Advances in Geo-Energy Research, 2017, 1(1): 18-30, doi: 10.26804/ager.2017.01.02

As a major supplement to conventional fossil fuels, unconventional oil and gas resources have received significant attention across the globe. However, significant challenges need to be overcome in order to economically develop these resources, and new technologies based on a fundamental understanding of flow and transport processes in unconventional reservoirs are the key. This special issue collects a series of recent studies focused on the application of novel technologies and theories in unconventional reservoirs, covering the fields of petrophysical characterization, hydraulic fracturing, fluid transport physics, enhanced oil recovery, and geothermal energy.

Natural stone has been a popular and reliable building material throughout history appearing in many historic monuments and in more recent buildings. Research into the intrinsic properties of specific stones is important because it gives us a greater understanding of the factors that limit and act on them. This can help prevent serious problems from occurring in our buildings bringing both esthetic benefits and financial savings. To this end, the main objective of this research has been to study the influence of the fabric and the mineral composition of two types of sandstone on their durability. The first is a red continental sandstone from the Buntsandstein Age called “Molinaza Roja”, which is quarried in Montoro (Cordoba). The second is quarried in Ronda (Malaga) and is sold under the trade name of “Arenisca Ronda”. It is a light pink-whitish calcarenite deposited during the Late Tortonian to Late Messinian. We characterized their petrological and petrophysical properties by studying their rock fabrics, porous systems and mechanical properties. In order to obtain a complete vision of the behavior of their rock fabrics, we also carried out two decay tests, the salt crystallization and the freeze–thaw tests. We then measured the effects on the textures of the altered samples during and after the decay tests and we evaluated the changes in the porous system. By comparing the results between intact and altered samples, we found that Arenisca Ronda is less durable because it has a high quantity of expandable clays (smectites) and a high percentage of pores in the 0.1–1 μm range, in which the pressure produced by salt crystallization is strongest. In Molinaza Roja the decay agents caused significant sanding due to loss of cohesion between the clasts, especially during the salt crystallization test. In both stones, the anisotropies (oriented textures) have an important role in their hydric and dynamic behavior and also affect their mechanical properties (especially in the compression resistance). No changes in color were detected. This study was financially supported by Research Group RNM179 of the Junta de Andalucía and by Research Project MAT2012-34473.

International audience; To assess the long-term safety of a geological carbon dioxide storage site, the confining properties of the rocks sealing an underground reservoir (caprocks) and their evolution inthe presence of CO2 must be characterized. The present study consists in the measurement of the transport parameters of dissolved CO2 through low permeability carbonate-rich caprocks. The properties of interest are the effective permeability and the diffusion coefficients of carbon dioxide dissolution products in water. The impact of carbon dioxide has been evaluated when altering rock samples by diffusion of a CO2-saturated brine under reservoir thermodynamic conditions, and by comparison of the pre- and post-alteration measured values. Permeability was measured by a gas-tracing method and, to study diffusion, radioactive isotopes of carbon (14C) and hydrogen (3H) were used. Despite a porosity increase observed for all the studied samples, the low values of transport parameters, measured initially, were also measured after alteration, showing a non-catastrophic alteration of the material.

Petrophysical properties including pore structure and permeability are essential for successful evaluation and development of reservoirs. In this paper, we use casting thin section and mercury intrusion capillary pressure (MICP) data to investigate the pore structure characterization, permeability estimation, and fractal characteristics of Carboniferous carbonate reservoirs in the middle blocks of the eastern margin of the Pre-Caspian Basin. Rock casting thin sections show that intergranular and intragranular dissolution pores are the main storage spaces. The pore throats greater than 1 μm and lower than 0.1 μm account for 47.98% and 22.85% respectively. A permeability prediction model was proposed by incorporating the porosity, Swanson, and R35 parameters. The prediction result agrees well with the core sample data. Fractal dimensions based on MICP curves range from 2.29 to 2.77 with an average of 2.61. The maximum mercury intrusion saturation is weakly correlated with the fractal dimension, while the pore structure parameters such as displacement pressure and median radii have no correlation with fractal dimension, indicating that single fractal dimension could not capture the pore structure characteristics. Finally, combined with the pore types, MICP shape, and petrophysical parameters, the studied reservoirs were classified into four types. The productivity shows a good correlation with the reservoir types.

Master's thesis in Petroleum geosciences engineering The results of the petrophysical evaluation of four turbidite systems located along the flanks of the Hammerfest Basin, in the southwestern Barents Sea, are presented in this master thesis. These systems are the reservoir of the Lower Cretaceous Clastic Wedges play in this area, which was proven successful in 2012, after drilling the Salina prospect. An environmental analysis, based on the study of cores and logs, shows that sand rich turbidite systems might be expected on the northeastern flanks of the Hammerfest Basin, sourced from the eastern Loppa High. Towards the northwestern and southwestern flanks, sand-mud rich system, sourced from the Loppa High and Finnmark Platform, are expected. This analysis, together with the results from the petrophysical evaluation, suggests a direct dependency of reservoir quality on depositional environment as well as on the type of turbidite system. A main challenge regarding petrophysical evaluations of these reservoirs is the scarce core data available within the Lower Cretaceous stratigraphic unit. Core data are very important for calibration of the parameters needed for the computation of the reservoir properties. The wells used in this study are among the few with core data available so the results could be calibrated. Therefore, these turbidite systems are proposed as analogues for future petrophysical evaluations of the Lower Cretaceous vii sandstone wedges when core data are not available. However, care should be taken in the use of these analogues since differences in the turbidites source area affect some of the petrophysical calculations. The results show that the computing parameters for the calculation of Vcl and PHIE/PHIT might be used independently from the reservoir’s source area. Yet, for permeability calculations, source area should be taken into consideration.

no abstract

Understanding oil systems requires petrographic characterization of all elements and process that compose it. In this work, several examples of source rocks, reservoir rocks and seal from different petroleum basins have been studied in order to describe conventional petrographic methods and develop new ones. The new ones as: a program of transformation kinetic of kerogene composed of two types of organic matter, maceral analysis and microfractures study using images analysis, the diffraction X-ray and tomography allowed source rock description. As for, reservoir rocks, methods of petrophysical characterization by images analysis, MSCL Microscopy and wettability parameters permit reservoir quality description and their preservation over time due to recrystalization and dissolution phenomena, fluid flow and TSR/BSR reaction. The cap rocks studied in this thesis are those of Callovo-Ordovician argillites, using X-Ray diffraction as well as images analysis and tomography. Those methods facilitated the understanding of argillites behavior over time, their sorption/desorption ability and their reliability of nuclear waste storage. Finally, Modeling using Petromod helps to determine petroleum systems functioning. Modeling by percolation method gives results closer to oil basins reality, than by Darcy/Hybrid method, La compréhension d'un système pétrolier nécessite la caractérisation pétrographique de tous les éléments et les processus le composant. Dans ce travail, plusieurs exemples de roches mères, roches réservoirs et roches couvertures provenant de bassins pétroliers différents, ont été étudiés afin de décrire les méthodes pétrographique classiques et mettre en place des nouvelles. Ces dernières telles que : la création d'une cinétique de transformation d'un kérogène composé de deux types de matière organiques (programmation), analyse macérale et l'étude des microfractures par analyse d'images, la diffraction à rayon X ainsi que la tomographie ont permis la caractérisation de la roche mère. Quant aux roches réservoirs, les méthodes d'analyse d'image des propriétés pétrophysiques, la microscopie MSCL ainsi que les paramètres de mouillabilité permettent la description de la qualité de ces réservoirs et leurs préservations au cours du temps à cause des phénomènes de recristallisation, dissolution, circulation de fluide et de réaction TSR/BSR. Les roches couvertures étudiées dans ce travail sont celles des argilites callovo-oxfordienne, utilisant la diffraction à rayon X ainsi que l'analyse d'image et la tomographie. Ces méthodes ont facilité la compréhension de leurs comportements au cours du temps, leurs capacités de sorption/désorption et leurs fiabilités de stockage de déchets nucléaire. Enfin, la modélisation pétrolière avec Petromod permet de déterminer les fonctionnements des systèmes pétroliers. La modélisation par percolation est plus proche de la réalité des bassins pétroliers que celle de Darcy/Hybride

In the framework of a wider European study of saline intrusions in coastal environments, the hydraulic behaviour of the rock matrix at the calcareous Campos site coastal aquifer (Majorca) has been characterized. This characterization is performed on rock cores in laboratory; its main objective is the relation between the hydraulic properties of the rock matrix and the rock forming components of petrophysical significance, specially the pore space structure. The anisotropy and heterogeneity is previously analyzed. The real and apparent density, effective and non-effective porosity, range of pore throat size, free and forced water absorption, water desorption, coefficient of capillarity and water vapour permeability have been evaluated. Seven different types of porosity according textural considerations have been established

In the framework of a wider European study of saline intrusions in coastal environments, the hydraulic behaviour of the rock matrix at the calcareous Campos site coastal aquifer (Majorca) has been characterized. This characterization is performed on rock cores in laboratory; its main objective is the relation between the hydraulic properties of the rock matrix and the rock forming components of petrophysical significance, specially the pore space structure. The anisotropy and heterogeneity is previously analyzed. The real and apparent density, effective and non-effective porosity, range of pore throat size, free and forced water absorption, water desorption, coefficient of capillarity and water vapour permeability have been evaluated. Seven different types of porosity according textural considerations have been established